This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
5hbc
From Proteopedia
Intermediate structure of iron-saturated C-lobe of bovine lactoferrin at 2.79 Angstrom resolution indicates the softening of iron coordination
Structural highlights
FunctionTRFL_BOVIN Transferrins are iron binding transport proteins which can bind two Fe(3+) ions in association with the binding of an anion, usually bicarbonate.[1] [2] Lactotransferrin has antimicrobial activity. The most effective inhibitory activity was seen against E.coli and P.aeruginosa.[3] [4] Lactoferricin B is an antimicrobial peptide. Inhibits the growth of Gram-negative and Gram-positive bacteria.[5] [6] The lactotransferrin transferrin-like domain 1 functions as a serine protease of the peptidase S60 family that cuts arginine rich regions. This function contributes to the antimicrobial activity.[7] [8] Publication Abstract from PubMedThe bilobal lactoferrin is an approximately 76 kDa glycoprotein. It sequesters two Fe(3+) ions together with two CO32- ions. The C-terminal half (residues, Tyr342-Arg689, C-lobe) of bovine lactoferrin (BLF) (residues Ala1-Arg689) was prepared by limited proteolysis using trypsin. Both C-lobe and intact BLF were saturated to 100%. Both of them retained up to nearly 85% of iron at pH 6.5. At pH 5.0, C-lobe retained 75% of iron whereas intact protein could retain only slightly more than 60%. At pH 4.0 both contained 25% iron and at pH 2.0 they were left with iron concentration of only 10%. The structure of iron saturated C-lobe was determined at 2.79 A resolution and refined to Rcryst and Rfree factors of 0.205 and 0.273, respectively. The structure contains two crystallographically independent molecules, A and B. They were found to have identical structures with an r.m.s. shift of 0.5 A for their C(alpha) atoms. A high solvent content of 66% was observed in the crystals. The average value of an overall B-factor was 68.0 A(2) . The distance of 2.9 A observed for the coordination bond between Fe(3+) ion and N(e2) of His595 appeared to be considerably longer than the normally observed values of 1.9-2.2 A. This indicated that the coordination bond involving His595 may be absent. Other coordination distances were observed in the range of 2.1-2.3 A. Based on the present structure of iron saturated C-lobe, it may be stated that His595 is the first residue to dissociate from ferric ion when the pH is lowered. Proteins 2016; 84:591-599. (c) 2016 Wiley Periodicals, Inc. Structure of iron saturated C-lobe of bovine lactoferrin at pH 6.8 indicates a weakening of iron coordination.,Rastogi N, Singh A, Singh PK, Tyagi TK, Pandey S, Shin K, Kaur P, Sharma S, Singh TP Proteins. 2016 May;84(5):591-9. doi: 10.1002/prot.25004. Epub 2016 Feb 24. PMID:26850578[9] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
| ||||||||||||||||||||
Categories: Bos taurus | Large Structures | Kaur P | Rastogi N | Sharma S | Singh A | Singh PK | Singh TP | Tyagi TK
